qt_internal_undefine_global_definition disables an internal global
definition that is defined by the qt_internal_add_global_definition
function for a specific target.
Remove the ability to set the custom "undefine" flag for the
definitions since it's hard to control it using the introduced
function.
Pick-to: 6.2 6.3
Task-number: QTBUG-100334
Change-Id: Ic1637d97aa51bbdd06c5b191c57a941aa208d4dc
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
fd3341a74e